Conversion of hydrocarbon oils



Sept. 20, 1938., c. H. ANGELL CONVERSION OF HYDROCARBON OILS Filed Aug.5, 1935 TTORNEY INVENTOR Patented Sept. 20, 1938 CONVERSEN l?HYQDRGCARBO OILS Y Charles H. Angell, Chicago, Ill., assignerto'Universal Oil Products Company, Chicago, Ill., a corporation ofDelaware Application August 5,

Claims.

This invention particularly refers to an improved process for theconversion of hydrocarbon oils accompanied by continuous coking of theresidual liquid conversion products wherein charging stock for theprocess, comprising hydrocarbon oil of relatively high-boilingcharacteristics or an oil containing a substantial proportion ofhigh-boiling materials, is subjected to vaporization by being commingledwith hot vaporous products from the coking stage of the process and theresulting non-vaporous high-boiling components of the charging stockeither subjected to coking together with said residual liquid conversionproducts or subjected to relatively mild conversion in a reactionchamber of the cracking system preceding the coking stage by contacttherein with highly heated products from the cracking coil of thesystem.

One of the most satisfactory methods which has been developed for thecontinuous coking oi relatively heavy oils, such as high-boilingresidual oils resulting from pyrolytic conversion, comprises passing theoil through a heating coil wherein it is quickly heated to a highconversion temperature under non-coking conditions and introducingthehighly heated oil into an enlarged coking zone, preferably operatedat substantially atmospheric or relatively low superatmosphericpressure, wherein its reduction to substantially dry coke isaccomplished.

In such methods of operation there is a large amount of available heatin the vaporous products evolved during the coking operation due to therelatively high temperature to which the heavy oils subjected to cokingare heated and, in accordance with the usual practice, a largeproportion of this available heat is wasted. Also due to the hightemperature and relatively low pressure employed in the coking operationthe vaporous products from the coking Zone normally contain aconsiderable amount of high-boiling materials, including entrained ordissolved tars and pitch-like material, unsuitable for conversion in theheating coil of the system to which the normal reflux condensate issupplied.

In the present invention a large portion of the available heat in thevaporous products from the coking Zone is utilized to effect substantialvaporization of the hydrocarbon oil charging stock for the process bydirectly commingling the hot vaporous products from the coking zone withthe charging stock in a vaporizing zone succeeding the coking chamber.The partial cooling of the vaporous products from the coking zone thuseffected by their contact with the relatively cool 1935, Serial No.34,655

charging stock serves to remove the undersirable high-boiling materialsfrom the vaporous products, allowing only relatively clean vapors topass from the vaporizing chamber to the fractionating Zone of the systemwherein the normal reflux condensate which is supplied to the heatingcoil of the cracking system is recovered. The undesirable high-boilingmaterials removed from the vaporous products of the coking operation bycontact with the charging stock in the vaporizing chamber commingle withthe high-boiling components of the charging stock remaining unvaporizedin this zone and, in accordance with the process of the presentinvention, these commingled relatively high-boiling materials may besupplied either to the heating coil of the coking stage or are directedwithout additional heating to the same high-pressure reaction chamber ofthe cracking system to which the highly heated products from the heatingcoil of the cracking stage are supplied.

It will be understood, of course, that the two alternative methods ofoperationV with respect to the disposition of the commingledhigh-boiling oils from the vaporizing chamber are not to be consideredequivalent but may be selected, depending primarily upon thecharacteristics of the commingled oils, to give the best results withrespect to yield of the desired products, continuity of operation,throughput, etc.

In one embodiment, the invention comprises subjecting hydrocarbon oil,comprising insufciently converted intermediate liquid products of theprocess, to conversion yconditions of cracking temperature andsubstantial superatmospheric pressure in a heating coil andcommunieating reaction chamber, withdrawing both vaporous and liquidconversion products from the reaction chamber and introducing the sameinto a reduced pressure vaporizing chamber wherein separation of vaporsand residual liquid conversion products is accomplished, withdrawingnon-vaporous residual liquid from the vaporizing chamber, heating thesame to a high conversion temperature under non-cracking conditions in aseparate heating coil, introducing the highly heated residual oil into acoking Zone wherein its reduction to substantially dry coke isaccomplished introducing vaporous products withdrawn from the cokingzone and vaporous products from the vaporizing chamber into a separatevaporizing chamber, introducing hydrocarbon oil charging stock for theprocess into said separate vaporizing chamber in contact with thevaporous products supplied thereto, subjecting the result- 55 ingvaporous products from said separate vaporizing chamber tofractionation, returning the resulting reux condensate to the firstmentioned heating coil, subjecting fractionated vapors of the desiredend-boiling point to condensation, collecting and separating theresulting distillate and gas, withdrawing from said separate Vaporizingchamber high-boiling components of the charging stock which remainunvaporized in this zone, together with high-boiling materials removedfrom the vaporous products supplied thereto, and introducing the sameinto the reaction chamber wherein they are subjected to relatively mildconversion by contact in this zone with the highly heated products fromthe rst mentioned heating coil.

As an alternative to the specific embodiment of the process abovedescribed the high-boiling oils from said separate vaporizing chambermay be supplied to the heating coil of the coking stage of the system,together with the non-vaporous residual liquid products from the firstmentioned vaporizing chamber, being thereby heated to a high temperatureunder non-coking conditions and subjected to coking in the succeedingcoking zone.

The accompanying diagrammatic drawing illustrates one specic form ofapparatus embodying the features of the present invention and in whichthe process of the invention may be accomplished.

Referring' to the drawing, heating coil I is located within a furnace 2of any suitable form by means of which the oil supplied to this zone, inthe manner to be later more fully described, is heated to the desiredconversion temperature preferably at a substantial superatmosphericpressure and the resulting highly heated products are directed from theheating coil through line 3 and valve 4 into reaction chamber 5.

Reaction chamber 5 is also preferably maintained at a substantialsuperatmospheric pressure and this zone is preferably well insulated,although insulation is not shown in the drawing, in order to prevent theexcessive loss of heat by radiation so that conversion of the heatedproducts, and particularly their vaporous components, may continue inthis zone. In the case here illustrated both vaporous and liquidconversion products are withdrawn in commingled state from the lowerportion of chamber 5 and are directed through line 6 and valve I intoVaporizing and separating chamber 8. It is, of course, also within thescope of the present invention to separately withdraw vaporous andliquid conversion products from the reaction chamber in which case thevaporous products separately withdrawn from this zone at any desiredpoint or plurality of points therein may be separately supplied, by wellknown means, not illustrated, to vaporizing chamber 8 at any desiredpoint or plurality of points in this Zone or they may be directed, allor in part, to vaporizing chamber 26 or to fractionator 34 or, whendesired, to coking chamber 2I by well known means, not shown.

Vaporizing chamber 8 is preferably maintained at a substantially reducedpressure relative to that employed in reaction chamber 5 by means ofwhich appreciable further vaporization of the liquid conversion productssupplied to this zone from the reaction chamber is accomplished.Separationof vapors and non-vaporous residual liquid is accomplished inchamber B, the vapors being withdrawn from the upper portion of thiszone through line 9 and valve I0, and they may be supplied through lineII, all or in part, to vaporizing chamber 26 or they may be supplied,all or in part, by well known means, not illustrated, to fractionator34. ,Residual liquid conversion products remaining unvaporized inchamber 8 are withdrawn from the lower portion of this zone through lineI2 and valve I3 to pump I4 by means of which they are fed through lineI5, valve I6 and line 54 to heating coil I'I.

Heating coil Il is located within a furnace I8 and this heating coil andfurnace are preferably of such design, which is now well known, that therelatively heavy oil supplied thereto, which is preferably passedthrough the heating coil at a relatively high velocity, is quicklyheated to a high conversion temperature without allowing it to remain inthe heating coil and communicating lines for a suflicient length of timeto permit any excessive formation and deposition of coke in this zone.The highly heated residual oil is directed from heating coil Il throughline I9 and valve 20 into coking chamber 2| wherein it is reduced tosubstantially dry coke by Virtue of its highly heated condition.

The coke produced in chamber 2I may be allowed to accumulate in thiszone to be removed therefrom in any suitable well known manner, notillustrated, after the operation of the chamber is completed. Although,for the sake of simplicity, only one coking chamber is shown in thedrawing twoI or more such zones are preferably employed and may beoperated simultaneously or, preferably, are alternately operated,cleaned and prepared for further operation in order that the cokingstage, in common with the rest of the system, may be operatedcontinuously. Chamber 2I is provided with a suitable drain-line 22controlled by valve 23 which may also serve as a means of introducingsteam, water or any other suitable cooling material into the chamberafter its operation is completed and after it has been isolated from.the rest of the system in order to hasten cooling of the chamber andfacilitate the removal of coke therefrom. Vaporous products evolved inchamber 2I are withdrawn from the upper portion of this zone throughline 2liV and valve 25 and are directed through line II to vaporizingand separating chamber 26.

Hydrocarbon oil charging stock for the process, which may comprise anydesired type of oil .f

but is preferably either an oil of relatively wide boiling range, suchas crude petroleum, topped crude, or the like, or an oil of high boilingcharacteristics, is supplied through line 2l and valve 28 to pump 29 bymeans of which it is fed through line 30 and valve 3| into vaporizingchamber-26 wherein it is intimately contacted with the hot vaporousproducts from the coking zone, as Well as, when desired, from vaporizingchamber 8 and/cr reaction chamber 5, and thereby subjectedtc'appreciable vaporization. It will be understood, of course, that thecharging stock may, When desired, be preheated to any desiredtemperature below that of the vaporous products with which it iscontacted in chamber 26, prior to its introduction into this zonealthough, for the sake of simplicity, none of the Well known means foraccomplishing this are illustrated in the drawing. Cooling of the, hotvaporous products supplied to chambers 25 by contact with the charging.stock in this Zone serves to remove therefrom undesirable high-boilingcomponents including any tarry or pitch-like material dissolved orentrained in the vaporous products from the coking zone. Accuratecontrol of the degree of vapori- Zation to which the charging stock issubjected in chamber 26 and the characteristics of the highboilingcomponents of the charging stock and vaporous products recovered asliquid from chamber 26 may be obtained by controlling the quantity andtemperature of the charging stock supplied to the vaporizing chamber andthe pressure conditions maintained in this zone. The relativelylow-boiling components of the charging stock which are vaporized inchamber 25 and the components of the vaporous products supplied to thiszone which remain uncondensed therein are directed through line 32 andvalve 33 to fractionation in fractionator 35i.

The components of the vaporous products supplied to fractionator 34boiling above the endboiling point of the desired iinal light distillateproduct of the process are condensed in this zone as reflux condensatewhich is withdrawn from the lower portion of the fractionator throughline 35 and Valve 36 to pump 3l by means of which it is supplied throughline 38 and valve 39 to con- Version in heating coil l, in the mannerpreviously described. Fractionated vapors of the desired end-boilingpoint are withdrawn, togethei` with uncondensable gas produced by theprocess, from the upper portion of the fractionatcr through line 4l! andvalve l! and are subjected to condensation and cooling in condenser G2.The resulting distillate and gas passes through line 63 and Valve lli tocollection and separation in receiver 5. Uncondensable gas may bereleased from the receiver through line 4B and valve lll. Distillate maybewithdrawn from receiver t5 through line i8 and valve is to storage orto any desired further treatment. A regulated portion of the distillatecollected in receiver l5 may, when desired, be recirculated by wellknown means, not illustrated, to the upper portion of fractionator Silto serve as a cooling and refluXing medium for assisting thefractionation of the vapors and to maintain the desired vapor outlettemperature from the fractionator.

High-boiling components of the charging stock remaining unvaporized inchamber 2t commingle in this zone with the high-boiling components ofthe vapors removed therefrom by contact with the charging stock and thecommingled materials are removed from the lower portion of chamber Bthrough line 55 and valve 5i to pump 52 by means of which they are fedthrough line 53 and may be directed through valve 5 and line 55 intoheating coil il, to be subjected to heating in this zone together withthe residual liquid conversion products from chamber 8 and subjected tosubsequent reduction to coke in coking chamber 2l or, as an alternativemethod of operation, all or a regulated portion of the commingledhigh-boiling oils from chamber 26 may be directed through valve 56 inline 53 into reaction chamber 5 preferably being sprayed against thewalls of the chamber by means of a suitable spreader flange or sprayarrangement such as indicated, for example, at 5l. By the latter methodof operation the high-boiling oils from chamber 26 are subjected torelatively mild conversion in chamber 5 by contact with the highlyheated products from heating coil l, the resulting vaporous and liquidconversion products commingling with the vaporous and liquid productsresulting from conversion of the lower boiling oils supplied to heatingcoil i and being subjected, in the portions of the cracking systemsubsequent to chamber 5, to the same conditions of further treatmentpreviously described.

In a process of the character illustrated and above described thepreferred range of operating conditions may be approximately as follows:The heating coil of the cracking stage of the system to which reiluxcondensate from the fractionator is supplied may utilize an outletconversion temperature ranging, for example, from 850 to 1000 F.,preferably with a superatmospheric pressure measured at the outlet fromthe heating coil of from to 800 pounds, or thereabouts, per square inch.A substantial superatomspheric pressure, which may be substantially thesame or somewhat lower than the pressure employed in the heating coil,may be utilized in the succeeding reaction chamber and the vaporizingchamber to which the liquid conversion products or both liquid andvaporous conversion products from the reaction chamber are suppliedpreferably employs a substantially reduced pressure relative to that inthe reaction chamber which may range, for example, from pounds, orthereabouts, per square inch down to substantially atmospheric pressure.The temperature employed at the outlet from the heating coil of thecoking stage of the system may range, for example, from 900 to 1050 F.preferably with a superatmospheric pressure in this zone of from 20 to150 pounds, or thereabouts, per square inch, although lower or higherpressures may be employed, when desired. The coking chamber may beoperated at any desired pressure ranging from 150 pounds, orthereabouts, per square inch down to substantially atmospheric pressure,which pressure, however, is no greater than that employed in thepreceding heating coil. Th-e vaporizing and separating chambersucceeding the coking chamber, to which charging stock for the processis supplied, may utilize any desired pressure from substantiallyatmospheric to 150 pounds, or thereabouts, per square inchsuperatmospheric pressure which, however, is no greater than thepressure employed in the coking chamber. The pressures employed in thefractionating, condensing and collecting portions of the system may besubstantially the same or somewhat lower than the pressure employed inthe last mentioned vaporizing and separating chamber.

As a specific example of one of the many possible operations of theprocess as it may be accomplished in an apparatus of the characterillustrated and above described, the charging stock, which comprises an18 A. P. I. gravity Mid-Continent reduced crude, is supplied to avaporizing chamber to which vaporous products from the coking zone ofthe system are also supplied and contacted with the charging stock,vaporous products from this zone are supplied tp the fractionator of thesystem and the resulting reflux condensate is subjected in a heatingcoil to van outlet conversion temperature of approximately 950 F. at asuperatmospheric pressure of about 350 pounds per square inch.Substantially the same pressure is maintained in the succeeding reactionchamber and the resulting vaporous and liquid conversion products aresupplied to a separate vaporizing chamber maintained at asuperatmospheric pressure of about 50 pounds per'square inch. Vaporousproducts from this zone are supplied to the rst mentioned vaporizingchamber while the high-boiling non-vaporous oils from both vaporizingchambers are supplied to a separate heating coil wherein they arequickly heated to an outlet temperature of approximately 980 F. at asuperatmospheric pressure of about 30 pounds per square inch and thehighly heated heavy oils are introduced into alternately operated cokingchambers maintained at substantially the same pressure. The pressureemployed in the coking chamber is substantially equalized in thesucceeding vaporizing chamber and in the fractionating, condensing andcollecting portions of the system. This operation will produce, perbarrel of charging stock, approximately 55 per cent of motor fuel havingan octane number of approximately 70 by the motor method andapproximately 120 pounds of low volatile coke of uniform quality andgood structural strength, the remainder being chargeable, principally,to uncondensable gas.

I claim as my invention:

l. In a process for the conversion of hydrocarbon oils wherein oilrecovered from within the system is subjected to conversion conditionsof cracking temperature and substantial superatmospheric pressure in aheating coil, the resulting vaporous and liquid conversion productsseparated and the latter subjected to appreciable further vaporizationin a reduced pressure vaporizing chamber, the remaining non-vaporousresidual liquid heated to a relatively high temperature under non-cokingconditions in a separate heating coil and then introduced into a cokingchamber wherein its reduction to substantially dry coke is accomplished,the improvement which comprises imparting to said residual liquid in theseparate coil suilicient heat to effect its reduction to coke in thecoking chamber, withdrawing vaporous products from the coking chamberand contacting the same in a separate Vaporizing chamber with relativelycool hydrocarbon oil charging stock for the process, whereby thecharging stock is subjected to appreciable vaporization andy undesirablehigh-boiling c omponents are removed from the vaporous products,subjecting the remaining vapors to fractionation together with vaporousproducts from the firstmentioned vap'orizing chamber whereby theirinsufficiently converted components are condensed as reflux condensate,supplying reflux condensate recovered by said fractionation to the firstmentioned heating coil for said conversion, subjecting fractionatedvapors of the desired end-boiling point to condensation, and collectingthe resulting distillate.

2. In a process for the conversion of hydrocarbon oils wherein oilrecovered from within the system is subjected to conversion conditionsof cracking temperature and substantial superatmospheric pressure in aheating coil and communicating reaction chamber, the resulting vaporousand liquid conversio-n products separated and the latter subjected toappreciable further vaporization in a reduced pressure vaporizingchamber, the remaining non-vaporous residual liquid heated to a hightemperature under noncoking conditions in a separate heating coil andthe highly heated residual oil introduced into a coking chamber whereinits reduction to substantially dry coke is accomplished, the improvementwhich comprises imparting to said residual liquid in the separate coilsufficient heat to effect its reduction to coke in the coking chamber,withdrawing vaporous products from the coking chamber and comminglingthe same, in a separate vaporizing chamber, with relatively coolhydrocarbon oil charging stock for the process whereby the chargingstock is subjected to appreciable vaporizationand undesirablehigh-boiling components are removed from the vaporous products,subjecting the remaining vapors to fractionation together with vaporousproducts from the first-mentioned vaporizing chamber whereby theirinsufficiently converted components are condensed as reflux condensate,supplying reflux condensate recovered by said fractionation to the rstmentioned heating coil for said conversion, subjecting fractionatedvapors of the desired end-boiling point to condensation, collecting theresulting distillate, withdrawing from the last mentioned vaporizingchamber high-boiling components of the charging stock remainingunvaporized in this zone, together with said high-boiling materialsremoved from the vaporous products supplied to this zone, and supplyingthe same to said reaction chamber wherein they are subjected torelatively mild conversion by contact with the highly heated productsfrom the first mentioned heating coil.

3. A process as claimed in claim l wherein vaporous products from thefirst mentioned vaporizing chamber are supplied to said separatevaporizng chamber.

4. A process as claimed in claim 2 wherein Vaporous products from therst mentioned vaporizing chamber are supplied to said separatevaporizing chamber.

5. In a process for the conversion of hydrocarbon oils wherein oilrecovered from within the system is subjected to conversion conditionsof cracking temperature and substantial superatmospheric pressure in aheating coil, the resulting vaporous and liquid conversion productsseparated and the latter subjected to appreciable further vaporizationin a reduced pressure vaporizing chamber, the remaining non-vaporousresidual liquid heated to a relatively high temperature under non-cokingconditions in a separate heating coil and then introduced' into a cokingchamber wherein its reduction to substantially dry coke is accomplished,the improvement which comprises imparting to said residual liquid in theseparate coil suiiicient heat to effect its reduction to coke in thecoking chamber, withdrawing vaporous products from the coking chamberand contacting the same in a separate Vaporizing chamber with relativelycool hydrocarbon oil charging stock for the process, whereby thecharging stock is subjected to appreciable vaporization and undesirablehigh-boiling components are removed from the vaporous products,supplying liquid products of the contacting step from said separatevaporizing chamber to said separate coil, fractionating the uncondensedvapors from said separate vaporizing chamber and vaporous products fromthe firstmentioned chamber and supplying resultant reflux condensate tothe rst-mentioned coil, and finally condensing and collecting thefractionated vapors.

CHARLES H. ANGELL.

